1. Field of the Invention
The present invention relates to a simulation test system for thermal impact ageing of a power transmission insulator, and more particularly, to a simulation test system for thermal impact ageing of a power transmission insulator which simulation tests an influence of a forest fire on the power transmission insulator.
2. Description of Related Art
In general, a power transmission facility such as a high voltage electric wire is installed in a mountain area in which there is almost no visitor and it is therefore difficult to extinguish a forest fire quickly when the forest fire is generated around power transmission facility and heat and flame due to the forest fire cause great damage to the power transmission facility.
Although this damage of the power transmission facility by the forest fire is a cause of lowering in reliability of a power transmission system due to breakdown and interruption of power transmission lines, detailed studies on the damage of the power transmission facility by the forest fire is currently in poor condition. Also, since data for studies on an influence of the forest fire on the power transmission facility in a domestic forest environment are insufficient, various studies for finding out the cause of the breakdown including flashover and disconnection and preparing measures for the system operation when the forest fire is generated are required. Further, studies for deterioration properties and replacement standard of main power transmission facility after generation of the forest fire is also insufficient and it is urgent to prepare measures therefor.
Meanwhile, when the power transmission insulator is affected by the flame of the forest fire, interfacial stresses due to thermal impact are a main cause of deterioration and breakdown since the insulator is compositely constituted of different materials including porcelain, cement, bronze, and enamel.
Result of analyzing a flame temperature and properties of the forest fire based on that the power transmission insulator is exposed to the forest fire in the domestic forest condition (height, fuel condition) shows probability of being exposed to a temperature in a range of 200 to 800° C. if a clearance between the insulator and the earth is 2 to 6 meter when considering kinds of the domestic woods and height of the power transmission tower. Also, the result show that a rising time to the maximum flame temperature is about 60 seconds, a falling time is about 300 seconds and a retention time of the flame temperature is 60 to 200 seconds.
From FIG. 1, it can be found that a temperature distribution according to flame of the forest fire is, taken as a whole, from 100 to 300° C. From FIG. 1, it can also be found that the insulator can be exposed to heat at 800° C. or more for tens minutes or more in a large scale forest fire when radiant heat is activated.
Although this experimental result is an important factor for analyzing deterioration of the power transmission insulator by the thermal impact according to exposure to the forest fire, building and technical studies for an accelerated deterioration analyzing system based on such data is so far insufficient.
In a currently available thermal impact ageing test system, the test is implemented with varying a temperature from −60° C. to maximum 700° C. by applying heat in an electric heating manner. However, the conventional thermal impact ageing test system has a limitation in that it is difficult to control the maximum temperature of the flame of the forest fire (about 800° C.), and a temperature inducing thermal impact deterioration (about 300° C.), and thus there is a need for a simulation test system for controlling the maximum temperature of the flame of the forest fire sufficiently.